US5148176A - Measuring device - Google Patents

Measuring device Download PDF

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Publication number
US5148176A
US5148176A US07/728,872 US72887291A US5148176A US 5148176 A US5148176 A US 5148176A US 72887291 A US72887291 A US 72887291A US 5148176 A US5148176 A US 5148176A
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United States
Prior art keywords
face
blast
analysing means
ultrasonic
signal
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Expired - Fee Related
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US07/728,872
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English (en)
Inventor
Timothy A. Beattie
Jeffrey J. Felice
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Orica Explosives Technology Pty Ltd
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ICI Australia Operations Pty Ltd
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Assigned to ICI AUSTRALIA OPERATIONS PROPRIETARY LIMITED reassignment ICI AUSTRALIA OPERATIONS PROPRIETARY LIMITED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FELICE, JEFFREY J., BEATTIE, TIMOTHY A.
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Assigned to ORICA AUSTRALIA PTY LTD reassignment ORICA AUSTRALIA PTY LTD CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: ICI AUSTRALIA OPERATIONS PROPRIETARY LIMITED
Assigned to ORICA EXPLOSIVES TECHNOLOGY PTY LTD. reassignment ORICA EXPLOSIVES TECHNOLOGY PTY LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ORICA AUSTRALIA PTY LTD.
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping

Definitions

  • the present invention relates to the measurement of the performance of blasting operations, in particular to the measurement of face velocity.
  • Face velocity is an important parameter in assessing blast performance and relates directly to several factors which are central to the efficiency of a mining operation.
  • the amount of time spent moving material after a blast can be affected by the amount of material thrown clear by the explosive, or the heave, and this can be directly related to the initial face velocity: a high face velocity can indicate more throw and hence less rehandling.
  • a radar apparatus adapted to measure face velocity of blast faces in blasting operations
  • said radar apparatus comprises a doppler module, a parabolic reflector and a signal analysing means, the doppler module being located at or near the focal point of the parabolic reflector, and being capable of generating and receiving microwave signals, said doppler module additionally comprising a horn adapted to facilitate the transmittance of a generated microwave signal onto the parabolic reflector.
  • the face velocity radar illuminates all or a selected region of a blast face with microwave radiation.
  • the signal reflected from the blast face may be continuously monitored by the face velocity radar.
  • the rock movement which follows initiation of the blast results in a Doppler shift in the signal detected by the face velocity radar. This signal is able to be interpreted in terms of a velocity distribution of the rocks within the illuminated area.
  • FIG. 1 shows a face velocity radar (1) and its location with respect to the blast face (5).
  • a blasting operation involves the placement of a number of explosive charges in boreholes (6).
  • the face velocity radar (1) comprises a doppler module (2) which is located at the focal point of a parabolic reflector (3).
  • the doppler module (2) continuously generates a microwave signal which is transmitted through a horn (7) onto the parabolic reflector (3) the microwave signal illuminates a selected area of the blast face (5).
  • the microwave signal which illuminates the blast face (5) is reflected back from the blast face (5) to the face velocity radar (1).
  • the parabolic reflector (3) focusses the reflected signal into the doppler module (2).
  • the doppler module (2) converts the detected microwave signal into an electrical signal which is transmitted to a signal analysing means (4).
  • the signal analysing means (4) may comprise an amplifier to increase the signal to noise ratio of the electrical signal.
  • the electrical signal may be recorded by any convenient means.
  • the signal analysing means converts the electrical signal to a velocity profile of the blast face.
  • Laboratory calibrations and field trials of the radar unit indicate that it can measure rock velocities within the range of 3 m/s to 90 m/s with an accuracy of up to 0.1 m/s at distances of up to 900 m away from the rock face.
  • the focussing properties of the parabolic reflector rely on its exact shape and on manufacturing tolerances being less than one-tenth the size of the microwave wavelength which in this case is 12.4 mm.
  • the diameter of the parabolic reflector must be large enough that all of the beam emitted by the microwave unit is reflected off the parabolic reflector.
  • the exact position of the microwave unit near the focus of the parabolic reflector will affect reception area and signal strength.
  • the reflector is parabolic all the way to the outer rim, is turned out of aluminium, has a focal length of 420 mm and no part of the parabolic reflector is closer to or further from the Doppler module than 1.24 mm.
  • the microwaves are emitted by a K-Band CW Doppler Module of 5.0 ⁇ 0.2 VDC operating voltage, 150 mA maximum operating current and having a microwave power emission level of less than one-thousandth of the Australian Standard AS 2772-1985 recommendation of 1 mW per square centimeter for limited exposure at frequency of 24.15 GHz.
  • Attached to the Doppler Module is a horn which directs microwaves from the module to the parabolic reflector.
  • the horn of the current invention is designed to a shape and tolerance which concentrates microwaves onto as large as possible an area but with minimum leakage around the edges in order to maximise signal strength and radar reception efficiency.
  • An amplifier unit may be used to power the Doppler Module and amplify the signal from the module to facilitate recording.
  • the amplifier unit has a response curve which is flat to within 2% tolerance from 900 Hz to 15 kHz, and flat to within 5% tolerance from 500 Hz to 25 kHz, these frequency bands corresponding directly to velocity ranges of 5.6 to 93 m/s (at 2% accuracy) and 3 to 155 m/s (at 5% accuracy).
  • the raw signal may be analysed in several ways. Viewing this signal is not essential but it can give further information than that from the rock velocity distribution alone, and it may be viewed simply on a storage oscilloscope, or a digital recording system and computer if available.
  • the signal analysing means may be directly connected to the Doppler module or may be indirectly connected such that the signal analysing means is remote from the parabolic dish and Doppler module. Indirect connection of the signal analysing may be desirable where the signal analysing means is difficult to transport to the blast site or is not suitable for operation in the relatively hostile environment of a blast site.
  • the means of indirect connection may allow real-time analysis of the data such as via a signal transmitting device. More preferable, as radio transmitters and the like are often not permissible at blasting operations, the indirect connection may be achieved by a suitable recording means such as a tape recording device. The recording is then played back into the signal analysing means at a convenient time and location and the face velocity measurements obtained.
  • the final rock velocity distribution can be obtained by separating the time domain recording into its frequency components and this is normally done by Fourier transform on a computer or by a spectum analyser.
  • FIG. 2 A typical face velocity distribution for a quarry is shown in FIG. 2. Each peak within the distribution corresponds to a rock or series of rocks moving at one velocity. The detailed face velocity information obtained by the microwave radar is indicated by the complexity of the distribution.
  • FIG. 3 depicts an ultrasonic wave (1) of frequency f 1 , being directed towards moving objects (2) causing a return (or echo) frequency (3) of frequency f 3 , returns to the sender.
  • the return frequency is slightly shifted (doppler effect) from the transmitted frequency.
  • the frequencies f 3 are proportional to f 1 and the velocities of the projectiles relative to the transmitter (4) and the receiver (5).
  • the transmitter (4) emits a 40 kHz ultrasonic wave (1) which is emitted by a transducer (6).
  • the frequency is adjusted to suit the transducer using a variable resistor (7) connected to an oscillator (8).
  • the returning echo (3) is picked up by the receiver (5) and amplified by an amplifier (9) to a suitable level for the demodulation stage.
  • the demodulation is synchronous, homodyne or coherent detection.
  • the format of the demodulator is of the switching type but is not limited to it. It will be apparent that any synchronous (multiplier) detector could be used.
  • the output of the detector or mixer (10) are waves of frequencies f 1 +f 2 and f 1 -f 2 with the inputs being the transmitted frequency f 1 chopping frequency) and the returned frequency f 2 .
  • f 2 could be a number of different frequencies from different objects. Both f 1 -f 2 contain the same information about the doppler frequencies.
  • Ultrasonic waves of either frequency f 1 -f 2 or f 1 +f 2 can be chosen for measurement.
  • Filters (II) can be used to remove the frequency which is not required for analysis.
  • the frequency required for analysis passes through the filters (II) to the signal analysing means (12).
  • Any convenient analysis technique such as Fourier Transformation yields the velocities of the objects.
  • the current invention uses frequency f 1 -f 2 for analysis.
  • a low pass filter is used to extract the f 1 -f 2 frequency and reject all higher multiples and frequency f 1 +f 2 .
  • a suitable band pass filter may also be used to remove very low and very high frequencies outside the frequency range of interest.
  • the current invention has been used to measure rock velocities within the range of 2 m/s to 40 m/s at distances of 220 m to 500 m away from the rock face and showed median face velocities of 8 m/s.
  • the Doppler effect employed by the radar device as hereinabove described is also evident in other radiation bands.
  • the utility of present invention is not limited to employing microwave radiation.
  • Another radiation band suitable for measuring face velocities is the ultrasonic frequency band.
  • an ultrasonic device adapted to measure face velocity of blast faces in blasting operations wherein the ultrasonic device comprises an ultrasonic generator, a transmitting device, a receiving device and a signal analysing means wherein the transmitting device transmits ultrasonic radiation and the receiving device receives the radiation after it has been reflected from the blastface.
  • Ultrasonic devices are particularly suited for measuring face velocities of small areas of a blastface. As they are inexpensive to produce, they are often located close to the blastface where the ultrasonic radiation generated can be directed onto a small area of the rockface. Use of a parabolic reflector is optional. The ultrasonic device thus located can provide detailed information about these small areas in the first few moments after detonation of the blastface.
  • the signal analysing means or other suitable recording means are usually remotely located from the ultrasonic generator, transmitting device and receiving device.
  • a long connector such as a wire or electrical cable are usually suitable to enable adequate separation of the signal analysing means or recording device from the other elements of the ultrasonic device.
  • the face velocity radar provides a simple, accurate field technique for measuring face velocities.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
US07/728,872 1990-07-13 1991-07-12 Measuring device Expired - Fee Related US5148176A (en)

Applications Claiming Priority (2)

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AUPK116890 1990-07-13
AUPK1168 1990-07-13

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US5148176A true US5148176A (en) 1992-09-15

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US (1) US5148176A (fr)
CA (1) CA2046952C (fr)
MX (1) MX173887B (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5315306A (en) * 1993-07-30 1994-05-24 Hughes Aircraft Company Spray paint monitoring and control using doppler radar techniques
US20110228968A1 (en) * 2010-03-16 2011-09-22 Hon Hai Precision Industry Co., Ltd. Loudspeaker device with sound enhancing structure
US20120046898A1 (en) * 2010-08-18 2012-02-23 Board Of Regents Of The University Of Texas Systems and methods for pressure measurement using optical sensors
CN106247875A (zh) * 2016-07-25 2016-12-21 贵州新联爆破工程集团有限公司 一种用雷达探测地质条件并进行爆破设计的方法
CN108801637A (zh) * 2018-06-08 2018-11-13 安徽大学 一种用于列车轴承轨边声学检测的抛物面声镜阵列采集装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU66204A (en) * 1904-06-01 1905-05-30 Edwin Phillips Improvements in mixing valves for explosion engines
US3731306A (en) * 1972-01-24 1973-05-01 Us Navy Sea state analyzer using radar sea return
US3938147A (en) * 1959-05-19 1976-02-10 The United States Of America As Represented By The Secretary Of The Army Frequency modulated doppler distance measuring system
US4271411A (en) * 1978-05-31 1981-06-02 Tdk Electronics Co., Ltd. Detector for doppler device
US4358835A (en) * 1979-12-27 1982-11-09 Bertin & Cie Method and device for matching the reflector of an acoustic echo ranging system
US4443792A (en) * 1980-08-29 1984-04-17 Coal Industry (Patents) Limited Electromagnetic position detector employing fast fourier transform analysis
US4641138A (en) * 1975-11-06 1987-02-03 Lockheed Electronics Co., Inc. Radar apparatus for detecting an agitated reflective target
US4673940A (en) * 1982-11-18 1987-06-16 The United States Of America As Represented By The Secretary Of The Army Detection of vibrating target signatures

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU66204B (en) * 1904-06-01 1905-05-30 Edwin Phillips Improvements in mixing valves for explosion engines

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU66204A (en) * 1904-06-01 1905-05-30 Edwin Phillips Improvements in mixing valves for explosion engines
US3938147A (en) * 1959-05-19 1976-02-10 The United States Of America As Represented By The Secretary Of The Army Frequency modulated doppler distance measuring system
US3731306A (en) * 1972-01-24 1973-05-01 Us Navy Sea state analyzer using radar sea return
US4641138A (en) * 1975-11-06 1987-02-03 Lockheed Electronics Co., Inc. Radar apparatus for detecting an agitated reflective target
US4271411A (en) * 1978-05-31 1981-06-02 Tdk Electronics Co., Ltd. Detector for doppler device
US4358835A (en) * 1979-12-27 1982-11-09 Bertin & Cie Method and device for matching the reflector of an acoustic echo ranging system
US4443792A (en) * 1980-08-29 1984-04-17 Coal Industry (Patents) Limited Electromagnetic position detector employing fast fourier transform analysis
US4673940A (en) * 1982-11-18 1987-06-16 The United States Of America As Represented By The Secretary Of The Army Detection of vibrating target signatures

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
Hamid et al., "Monitoring the Velocities of Particulates Using Doppler Radar", Journal of Microwave Power, 10(2), Jul. 1975, pp.163-170.
Hamid et al., Monitoring the Velocities of Particulates Using Doppler Radar , Journal of Microwave Power, 10(2), Jul. 1975, pp.163 170. *
M. I. Skolnik, "Radar Handbook", McGraw-Hill, 1970, pp. 10-1 to 10-10.
M. I. Skolnik, Radar Handbook , McGraw Hill, 1970, pp. 10 1 to 10 10. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5315306A (en) * 1993-07-30 1994-05-24 Hughes Aircraft Company Spray paint monitoring and control using doppler radar techniques
US20110228968A1 (en) * 2010-03-16 2011-09-22 Hon Hai Precision Industry Co., Ltd. Loudspeaker device with sound enhancing structure
US8259965B2 (en) * 2010-03-16 2012-09-04 Hon Hai Precision Industry Co., Ltd. Loudspeaker device with sound enhancing structure
US20120046898A1 (en) * 2010-08-18 2012-02-23 Board Of Regents Of The University Of Texas Systems and methods for pressure measurement using optical sensors
CN106247875A (zh) * 2016-07-25 2016-12-21 贵州新联爆破工程集团有限公司 一种用雷达探测地质条件并进行爆破设计的方法
CN108801637A (zh) * 2018-06-08 2018-11-13 安徽大学 一种用于列车轴承轨边声学检测的抛物面声镜阵列采集装置

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Publication number Publication date
CA2046952C (fr) 2002-01-29
MX173887B (es) 1994-04-07
CA2046952A1 (fr) 1992-01-14

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